Self-aligned V-groove cleaving and low-temperature metallization for high-performance quantum-dot lasers on off-cut silicon

We report the monolithic integration of InAs/GaAs quantum dot laser diodes (QDLDs) on 4° off-cut Si (001) substrates using a fully MOCVD-grown process. A V-groove-assisted cleaving method and low-temperature ohmic contact formation were developed to address cracking and facet roughness inherent to off-cut substrates. The resulting devices exhibited low threading dislocation density (7 × 10 6 cm −2 ), high QD uniformity, and mirror-quality cleaved facets. Room-temperature continuous-wave lasing at 1298 nm with a threshold current of ∼310 mA and single-facet output power up to 50 mW was achieved. These results demonstrate a manufacturable route for Si-based QD light sources with high performance and thermal robustness up to 105 °C.